5 tips for reducing Legionella risk utilizing water management for construction and commissioning

There has been a lot of discussion and new guidance documentation about Legionella in building water systems and the implementation of water management programs (WMP) for ongoing operations. This has led to discussions about plumbing engineering best practices to allow the building water distribution system (BWDS) to operate efficiently and safely when the building is occupied.

However, even if the building is engineered to reduce the likelihood of waterborne pathogen growth and spread, the construction and commissioning phases of a project can completely derail even the best intentions of plumbing design professionals. The distinct phases of constructing and commissioning the BWDS can result in emerging disease cases or deaths immediately upon opening the facility. Who wants to celebrate a new building opening surrounded by a community outbreak of disease cases and deaths? It is certainly not something your clients, firm or professional liability insurance company would welcome.

Construction water risks

Construction activities since 1965 have been linked to Legionella outbreaks in community and healthcare settings. The nine known construction activities contributing to this problem are:

1. Excavation;
2. Re-pressurization;
3. Demolition activities;
4. Improper application of efficiency design;
5. Underground utility connections;
6. Construction equipment with water reservoirs;
7. Water main breaks;
8. Vibration activities; and
9. Lack of effective BWDS commissioning.

Most disease cases and deaths have occurred due to a lack of effective BWDS commissioning with no plan to assure safe water prior to opening the building to the public. A new area of research complementing the WMP movement, water management for construction (WMC), is closing this knowledge gap while also addressing water safety commissioning practices.  

Spreading the word

As WMC research grows, code and guidance organizations are exploring ways to best disseminate industry information on these topics. The International Association of Plumbing & Mechanical Officials (IAPMO ) has established a Construction Practice Task Force to examine recommendations to the plumbing engineering and construction disciplines. This task force is focused on creating a water management for construction and commissioning guidance document over a three-year cycle with the first publication targeted for 2025.

In the meantime, here are five key activities for design and construction teams to consider to jumpstart their knowledge of WMC practices.

Tip 1: Conduct a water safety risk assessment

In pre-design (or even immediately prior to construction), your team could benefit from reviewing:

A. BWDS construction activities and scope of work;

B. Building occupant construction exposure risk; and

C. Determine a WMC risk mitigation plan with hazard control activities (such as flushing, temperature checks, and disinfection protocols).

A novel tool for establishing water safety risk assessment for healthcare facilities using infection prevention and control methods is currently available. For non-healthcare buildings, “Water Safety Risk Assessment for Construction: Developing and Implementing a Tool for Academic Campus Organizations,” is an hour-long webinar explaining water safety risk assessments.

Tip 2: Develop a project schedule for BWDS water activation

Many of the construction activities for assembling the BWDS are already part of the project scope of work. Consider asking the general contractor and plumbing sub-trades to establish a BWDS water activation schedule that aligns with other critical project scheduling milestones. Establish key tasks with construction duration (start and end dates) including, but not limited to:

• BWDS main connection at point-of-entry;
• Installation of mains, risers, and branches;
• Installation of terminal fixtures by floor;
• Pressure testing;
• BWDS water activation (hot and cold lines);
• Flushing protocols;
• Final disinfection protocols; and
• Analytical water sampling.

All BWDS tasks need to be discussed with the building owner to align with contractual dates for substantial completion (e.g., building occupancy for fire and life safety) and first business/patient day of operations. Many construction project teams will need to discuss the length of time between substantial completion and first business day of operations to determine who will maintain flushing protocols. This schedule period is known for high-water stagnation creating opportunities for waterborne pathogen growth and spread.

Tip 3: Discuss alternative methods for early-stage construction water usage

Often, the general contractor prematurely activates the building owner’s BWDS in an early stage of construction to gain access to water as a utility function. The contractor uses water for establishing contractor hydration stations and restrooms, mixing materials (e.g., adhesives, grouts, concrete batching or mortar) or building demolition or assembly (e.g., dust suppression, hydro-demolition, power washing and drilling/cutting). This is much like using electricity to perform building construction work. However, a small amount of water use occurs during construction compared to the overall building water use during normal facility operations. Early filling of water piping allows for the early growth and spread of waterborne pathogens in the BWDS. Can the construction team consider an alternative water source or piping route for these functions and establish a water activation date later in the project schedule? Items to consider include:

1. Installing temporary water supply piping to be abandoned later;
2. Using air for pressure testing water fixtures; and
3. Only installing distribution piping near large water volume usage areas (e.g., shell and core areas) early on while delaying the installation of distribution piping until a later date.

Tip 4: Conduct a pre-construction conference on WMC practices

Some building owners have found success by conducting a WMC pre-construction conference to bring together the building owner’s WMP team, design and construction professionals to organize and discuss water safety expectations. This allows them to address such items as:

• BWDS project schedule milestones;
• Documentation (e.g., logs and reports) and communication methods;
• Local municipal water authority contact;
• Municipal disinfectant method (e.g., chlorine or chloramine);
• Disinfectant residual at the point-of-entry in parts per million (ppm);
• Need for supplemental disinfection systems;
• Flushing activities; and
• Disinfection protocols.

The team should also establish roles and responsibilities concerning who performs such work, frequency and the duration of activities throughout the construction project.  

Tip 5.  Analytical test methods and laboratory selection

Establishing WMP/WMC sampling plans and validation test methods can represent a complex analysis outside of the scope of a design professional or general contractor. In most states and local municipalities, the potable water BWDS test for pathogens or water chemistry does not typically extend beyond E. Coli and coliforms for water drinking criteria. However, inhalation from water aerosolization at sinks, showers or ice machines involves different types of analytical test methods.   

Furthermore, regulations regarding commissioning, recommissioning and activation of a BWDS were changed by many states during the COVID-19 pandemic response to stay-at-home orders and the continued evolution of WMC practices. If you are not familiar with the process for establishing BWDS water sampling plans, consider seeking information from a WMP consultant or analytical laboratory specializing in Legionella and waterborne pathogen testing. To determine a qualified consultant, the Centers for Disease Control and Prevention (CDC) offers Considerations when working with Legionella consultants which recommends examining seven characteristics before engagement. Additionally, the CDC has a list of laboratories with ELITE certification for Legionella testing.

How to learn more

Plumbing engineer professionals seeking water management training before engaging in these activities should consider the following:

The CDC’s “Preventing Legionnaires’ Disease: A Training on Legionella Water Management Programs (PreventLD Training):” This is a free online training course consisting of six modules and two case studies. It has an easy start and stop interface for self-paced learning and a certificate upon completion. Total run time is about three hours.

ASSE International Certification 12080: Paid for in-person training outlining the minimum qualifications needed, including knowledge and competency, to become a member of a water safety team involved in the development of a risk assessment analysis, and water management and sampling plan, for protection from Legionella and other waterborne pathogens.